1. Field of the Invention
The present invention relates to a compound having thieno[3,2-b]indole structure and to an organo-electroluminescent device using the same, and more particularly, to a thieno[3,2-b]indole-based polymer which has blue light-emitting characteristic and can be easily prepared, and to an organo-electroluminescent device using the polymer as an organic layer forming material.
2. Description of the Related Art
In general, an organo-electroluminescent device is constructed with an organic light-emitting layer which is interposed between a cathode and an anode. In the organic light-emitting layer, electrons and holes injected from the cathode and the anode are combined to generate excitons. Light is emitted as a result of the transition of the generated excitons from an excited state to a ground state.
With the developments of a laminated structure having an aluminum quinolinol complex layer and a triphenylamine derivative layer as disclosed in U.S. Pat. No. 4,885,211 entitled Electroluminescent device with improved cathode to Tang, et al. and issued on Dec. 5, 1989 and of a compound for forming the light-emitting layer using a low molecular weight compound as disclosed in U.S. Pat. No. 5,151,629 entitled Blue emitting internal junction organic electroluminescent device (I) to VanSlyke and issued on Sep. 29, 1992, organo-electroluminescent devices capable of emitting various light in the range of from ultra violet ray to infrared ray could be manufactured.
An organo-electroluminescent device using a conjugated polymer, polyphenylenevinylene (PPV), as a light-emitting layer forming material was proposed in Nature, Vol. 347, 539, 1990. Thereafter, a novel PPV-based polymer, which is dissolved in an organic solvent and has good chemical stability and luminous efficiency, and polyfluorene having better performance than the PPV-based polymer were developed. Polyfluorene has blue light-emitting characteristic, but does not have satisfactory color purity characteristic due to excimers derived from side chains of polyfluorene structure (WO 9705184 and U.S. Pat. No. 5,900,327 entitled Polyfluorenes as materials for photoluminescence and electroluminescence to Pei, et al. and issued on May 4, 1999).
To improve the color purity characteristic of polyfluorene, polyspirofluorene (U.S. Pat. No. 5,621,131 entitled Conjugated polymers having spiro centers and their use as electroluminescence materials to Kreuder, et al. and issued on Apr. 15, 1997), spirobifluorene, or hetero atom-containing spirofluorene (U.S. Pat. No. 5,763,636 entitled Polymers containing spiro atoms and methods of using the same as electroluminescence materials to Kreuder, et al. and issued on Jun. 9, 1998 and U.S. Pat. No. 5,859,211 entitled Conjugated polymers containing heterospiro atoms and their use as electroluminescence materials to Kreuder, et al. and issue on Jan. 12, 1999) structures were developed. However, these substances do not have sufficient lifetime, efficiency, reliance, processing ability, and color purity characteristics, and thus must be improved.